AbstractThe composition and the origin of raw materials used in the ancient mortars and concrete of the Nora theatre (first century AD) have been analysed to define their provenance and construction technologies of the Roman period.

The use of geomaterials in the binder / aggregate mixtures of the mortars vary according to their function in the different sectors (i.e., structure-wall, tribunalia vaults, wall of external niches, foundation of cavea tiers, stage inner wall) but also according to different construction phases of the theatre or the work-steps. The mortars with structural function are mainly hydraulic (e.g., concrete of vaults, jointing and foundation mortars of cavea ashlars), while the lime mortars were used mainly for plasters, and rarely as bedding mortars. As recommended by Vitruvius, in the hydraulic mortars were mainly used volcanic rocks, as coarse and fine pozzolanic aggregate (pulvis puteolanus), and quartz-feldspar sands (present as crystal-clasts with an almost constant ratio of about 2:1, respectively). The cocciopesto is anomalously rare or absent. In the mortars local dacitic volcanic rock were also used, especially in the concrete as caementia.

The grey-black volcanic rocks are glasses with characteristics more near to obsidian and less to natural pozzolan normally used in the Roman period. To identify the provenance of these glasses, a geochemical comparison between the samples taken from the theatre mortars and the volcanic outcrops of some probable Sardinian source areas is made by XRF and SEM-EDS / WDS analysis.

To verify the quality of the pozzolan (by its chemical reaction with the binder), the edges and inside of volcanic glasses were analysed with an SEM-EDS microprobe, while the compositional characteristics and the hydraulic degree of the binder was analysed with XRPD and TG/DSC methods, respectively.

The use of this kind of pozzolanic glass, without local origins, is a novelty because it has never been found in the mortars of the archaeological site of Nora. Given the wide use of Sardinian obsidian in the Neolithic or Calcolithic periods for production of tools and instruments, some considerations about its use, origin and trade are made.

AbstractShale gas is envisaged to contribute in the next future to the European energy mix in the prospective of lowering CO2 emissions. Poland is by far one of the most prospective countries in Europe. In the "Golden Belt", potential productive levels are Early Paleozoic in age and the reliable assessment of their thermal maturity is crucial for evaluating hydrocarbon generation/expulsion scenarios.

When exploring Early Paleozoic targets that are devoid of vitrinite macerals, uncertainties in thermal maturity evaluation can occur according to commonly adopted parameters (e.g., vitrinite reflectance). These uncertainties can negatively influence targets assessment.

We adopted a multi-method approach to assess thermal maturity of the Silurian sections encountered in three wells deep between 2.9 and 3.3 km, recently drilled in the Polish Baltic Basin.

The methodological strategy consists of: (i) measurement of organoclasts (mainly graptolites) reflectance; (ii) FT-IR spectroscopy on bulk dispersed organic matter; (iii) X-ray diffraction on <2 μm grain-size fraction of sedimentary core samples. Organoclasts reflectance is between 0.6 and 1.4% indicating a large range of thermal maturity spanning from early to late mature stages of hydrocarbon generation. Mixed layers illite-smectite and FT-IR indexes (e.g. CH2/CH3, A and C) allowed us to improve the definition of thermal maturity of Lower Paleozoic rocks (Roeq between 0.8 and 1.1%).

This original dataset indicates lower levels of thermal maturity than those predicted in pre-existing thermal maturity maps, suggesting that the Silurian sections experienced thermal maturity conditions equivalent to the oil window more than the gas window.

AbstractThis paper and the associated 1:50,000 geological map are devoted to describe the geological features of the Monte Amiata region. The tectono-stratigraphic setting of Monte Amiata region includes, from bottom to top, 1) the pre-Neogene stack of tectonic units, made up of Tuscan, Sub-Ligurian and Ligurian Tectonic Units, 2) the Neogene sedimentary deposits and 3) the Pleistocene Radicofani and Monte Amiata volcanoes. The pre-Neogene stack of tectonic units includes, from bottom to top, the Tuscan Nappe, belonging to the Tuscan Domain, and Canetolo Tectonic Unit, belonging to the Sub-Ligurian Domain. These tectonic units, regarded as representative of the thinned continental margin of the Adria plate, are topped by the Santa Fiora and Ophiolitic Tectonic Units, interpreted as remnants of the Ligure-Piemontese oceanic basin and its transition to the Adria continental margin. All the tectonic units of the pre-Neogene stack have been affected by folds and thrusts originated during the convergence related to the Europe-Africa motion during the Middle Eocene-Early Miocene. Subsequently, these tectonic units were affected by a widespread reduction of thickness of their successions due to low-angle normal faulting related to the Middle Miocene extensional tectonics. The Neogene sedimentary deposits unconformably overlie the pre-Neogene stack of tectonic units. They consist of Upper Miocene to Pliocene continental and marine sediments, filling the Cinigiano-Baccinello, Velona, and Siena-Radicofani basins, adopting an informal hierarchy of different stratigraphic units where the first order units are synthems. The Pleistocene Radicofani and Monte Amiata volcanoes are made up by high-K basaltic andesitic to shoshonitic volcanic rocks and by trachydacitic to trachytic and olivine-latitic volcanic rocks, respectively.The geological mapping has provided evidences of a complex tectonic setting resulting from a long-lived history shifting from Cretaceous to Early Miocene compressive events to Middle Miocene extensional tectonics and Late Miocene-Pleistocene contractional and extensional events during which the Pleistocene magmatic activity occurred. In this regard, the Monte Amiata region can be regarded as a key area where the final result of a 200 Ma long geological history of the Northern Apennines is exposed.

AbstractThe Arabescato Orobico is a decorative stone and building material from the Bergamasc Alps, Italy. From the geological standpoint it belongs to the Calcare Rosso, latest Ladinian-Early Carnian in age, which is a peritidal tepee-rich limestone strongly modified by superimposed early diagenetic processes, outcropping in Lombardy Southern Alps. In the last twenty-five years four commercial varieties have been available on the market, namely Grigio, Grigio-Rosa, Rosa, and Rosso, whose working and abandoned quarries, are located around the extraction districts of Camerata Cornello, and San Giovanni Bianco in the median Brembana Valley. Until the 1970s of the last century some different historical types, namely Rosso Antico, Rosso Venato, and Venato Finissimo, where extracted around Ardesio, in the Seriana Valley, as well. This paper deals with the stratigraphic analysis based on detailed physical correlations of several marker horizons mainly recognized along abandoned and active quarries, and their carbonate facies analysis. Stratigraphic results permit to divide the Calcare Rosso unit in three lithozones (CR1, CR2, and CR3), with a very low angle onlapping geometry at the top of the Esino Limestone. Southward (basinward) the Calcare Rosso gradually passes to dominant grey peritidal carbonates poor in tepee
horizons corresponding to the lower Breno Fm.. The petrographic characterization of representative samples from Mecca and Cadei quarries, permits to distinguish peculiar textural and compositional features of the four contemporaneous commercial types. As concerns the Grigio we identify almost five different subtypes, respectively
denominated Grigio Laguna, composed of fossiliferous subintertidal grey to dark grey and black wackestone-packstones, Grigio Granulare, composed of inter-supratidal pisolitic grey grainstonerudstones, Nero Raggiato, very rich in “raggioni”, dark grey to black fibrous-radial early diagenetic calcite, Grigio Laminato composed of poorly to middle deformed antiformal structures, namely embryo to mature tepees, and, finally, Grigio Brecciato, a grey-colored diagenetic-pedogenetic breccia. Remaining types, ascribed to pinkishgrey, Grigio-Rosa, pinkish, Rosa, and reddish, Rosso, colored diagenetic supratidal facies, can be divided into laminated or brecciated subtypes. The former are composed of antiformal syndepositional to early diagenetic structures, i.e. embryo to mature tepees; the brecciated subtypes consist of more diagenetically modified senile tepees passing to breccias. These types present different amounts of sediment filling, including internal calcitic and dolomitic sediments, pisolites, terra-rossa paleosols and green/reddish clays, and early cementation, such as fibrous isopachous crust, “raggioni”, sparry calcite, of the primary and early diagenetic cavities. The stratigraphic organization, and the facies analysis of this carbonate succession, have been used to evaluate the areal and vertical distribution of the Arabescato Orobico commercial types; in this way the Calcare Rosso depositional model is also suitable for geological prospecting and quarrying activities.

AbstractIn the Trasimeno Lake area (Umbria Region), several thrust sheets belonging to the Sansepolcro-Monte Filoncio and Rentella Units, are interposed between the Tuscan Nappe (in the hanging-wall) and the Umbria-Romagna Unit (in the footwall). The thrust sheets succession of the Sansepolcro-Monte Filoncio Unit is made up of Rupelian-Chattian Scaglia toscana Fm. and Chattian-Aquitanian foredeep deposits of Macigno Fm.; the base of the siliciclastic succession becomes gradually younger eastward. The compositional mode of the fine-grained rock fragments in the arenaceous turbidites is comparable with that of the upper part of the Macigno Fm. in the Tuscan Nappe.

The succession of the Rentella Unit includes Rupelian-Aquitanian Monte Rentella Fm. and Aquitanian-Burdigalian foredeep siliciclastic turbidites of the Montagnaccia Fm.. In the lower portion of the Montagnaccia Fm. a level of black cherty horizons is present, as detected in all Aquitanian-Burdigalian successions of the Northern Apennines. The compositional mode of the fine-grained rock fragments in the turbidites is comparable with that of Marnoso-Arenacea Fm..

All these data allow an Oligocene-Miocene paleogeographic reconstruction of the Northern Apennines foredeep. Based on the age, the compositional mode and structural position, the Rentella and Sansepolcro-Monte Filoncio Units can be compared to the Carigiola and Acquerino Units cropping out in the Tuscan-Emilian Apennines.

AbstractIn the Northern Apennines, the Poggio Carnaio Sandstone Formation consists of sandy-clayey turbidites, cropping out in the northernmost corner of the Val Marecchia Nappe.

The formation has been considered Oligocene in age and is commonly interpreted as an Epiligurian unit, unconformably deposited above the Val Marecchia Nappe during its transport towards the Adriatic foreland.

The Poggio Carnaio Sandstone Fm rests on the Argille Varicolori Fm of the Val Marecchia Nappe, but field data do not allow it to be recognized wherever it abruptly replaces the pelagic sediments of the Argille Varicolori Fm, thus testifying to the foredeep evolution of the basin, or where it unconformably overlies this latter formation.

Nannofossil assemblages are characterized by abundant reworked Cretaceous and Paleogene taxa and by some taxa, whose first occurrence is reported in the upper part of the NN4 Zone = upper part of the CN3 Zone. Therefore the formation must be considered not older than Langhian.

Detrital modes of arenites revealed a quartz-feldspathic composition and the lithic component includes mainly metamorphic fragments and minor plutonic, sedimentary, ophiolithic and volcanic clasts. The presence of clasts of garnet, sillimanite, hornblende and glaucophane is significant. Biostratigraphic as well as petrographic data agree with the interpretation of the Poggio Carnaio Sandstone Fm as an Epiligurian succession.

Rock fragments indicate source areas characterized by Ligurian-, Pennidic- and Australpine-type units. Sedimentary facies and textural features of arenites, revealing a rapid erosion and deposition of clasts in a basin close to the source area of the clastic supply, indicate that the Alps cannot be considered as the source area of these arenites, as frequently argued for many North-Apennine clastic formations. Ligurian-, Pennidic- and Australpine-type units were located close to the Poggio Carnaio Sandstone basin, probably representing the geometrically highest units of the Palaeo-Apennine Chain.